1. Field of the Invention
The present invention relates to a torque converter for arrangement in a motor vehicle between an internal combustion engine and an automatic transmission, including a converter housing that has a plurality of connection areas on one axial side of the converter housing. The converter housing is connectable in a rotation-proof fashion to a crank shaft or to a component securely attached or attachable thereto by coupling elements positioned in the connection areas. The connector housing also includes and a plurality of substantially radially extending hollows arranged at a distance from each other in the circumferential direction.
2. Description of the Related Art
In the type of torque converters that are the subject of the present invention, a converter housing is connectable to a crank shaft of an internal combustion engine or to a flex plate or other component connectable with the crank shaft, and also carries a pump wheel. A turbine wheel is arranged inside the converter housing so as to be rotatable relative to the pump wheel. The converter housing also forms a fluid space in which a working fluid is held. The working fluid transmits torque between the pump wheel and the turbine wheel.
During operation of this type of torque converter, very great pressures of the working fluid are produced. Therefore, care must be taken to ensure that the converter housing is not deformed by the working fluid overpressure exerted on it from the inside. Furthermore, in constructing the converter housing, it is important to ensure that coupling elements are attached to the converter housing on the axial side on which the torque converter is to be connected to the crank shaft. Torque converters according to the prior art have converter housings with hollows extending radially outward from the radial inside on the axial sides of the converter housing intended for connection to the internal combustion engine. The hollows are arranged symmetrically relative to the rotational axis to allow the thinnest possible metal sheets to be used in manufacturing the torque converter housing. Generally, there are six hollows which run from a radially inner area to a radially outer area of the converter housing at an angular distance of 60.degree. to each other. These hollows ensure sufficient rigidity of the converter housing when relatively thin materials are used. For connecting to the crank shaft or to a flex plate or other component attached in rotation-proof manner to the crank shaft, coupling elements are welded to the converter housing, for example, in the areas between the individual hollows. The coupling elements have threaded openings. Screw bolts that penetrate corresponding openings in the crank shaft or other component are threaded into the threaded opening of the coupling elements.
A problem with the prior art converter housings is that because there are, for example, six hollows, a like number of coupling elements must be provided and then connected to the converter housing either in the areas between the individual hollows or directly in the hollows themselves. To guarantee true running, the coupling elements attached to the converter housing must be distributed symmetrically. When six hollows are provided, the single alternative is to provide three coupling elements at an angular distance of 120.degree.. However, when three coupling elements are provided, the forces that result from torque transmission in the areas where the individual coupling elements are attached to the converter housing become very large and may lead to deformation of the converter housing.